This study investigates the long-term impact of global trade wars on supply chain performance in West Africa, with particular attention to sectoral vulnerabilities in agriculture across Nigeria, Ghana, Senegal, Mali, and Niger from 1994 to 2025. Adopting a quantitative longitudinal research design, the study leverages secondary data from the World Trade Organization, United Nations Comtrade, World Bank, national statistical agencies, and the Economic Community of West African States. Trade war intensity is proxied by average tariff rate changes, while supply chain performance is measured using a composite index of trade volume, logistics performance, and lead times. Complementary macroeconomic controls include GDP, trade openness, and the Logistics Performance Index. Panel econometric techniques are employed to examine cross-country and temporal dynamics. Descriptive statistics reveal moderate variability in supply chain performance and high volatility in tariff movements. Correlation analyses indicate a significant negative relationship between trade war intensity and supply chain performance, with the agricultural sector showing pronounced vulnerability. Panel unit root tests (LLC, IPS, Fisher-ADF) confirm that all variables are non-stationary at levels but stationary at first differences, supporting the application of fixed-effects and dynamic panel regressions. Fixed-effects estimations demonstrate that a one-percentage-point increase in average tariffs reduces supply chain performance by 0.28 units, while the impact on agriculture is amplified, with total marginal effects of 0.41 units. Dynamic GMM analysis further confirms the persistence of trade war shocks, with logistics infrastructure, trade openness, and economic scale mitigating adverse effects. Country-level heterogeneity reveals that landlocked economies, particularly Mali and Niger, are more vulnerable due to higher transit dependence. The findings underscore that trade wars constitute structural shocks to West African supply chains, with differentiated sectoral and national impacts. Policy implications include strengthening regional value chains, promoting domestic input production, improving logistics infrastructure, diversifying trade portfolios, and establishing contingency mechanisms to buffer trade disruptions. By integrating cross-country and sectoral analyses over three decades, this study contributes novel longitudinal evidence on the structural effects of global trade tensions in developing regional contexts.